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#pragma once
#include "../util/native.h"
namespace pe {
class virtual_image {
std::unordered_map<std::string, uintptr_t> m_exports;
IMAGE_NT_HEADERS64* m_nt;
uintptr_t m_base;
public:
virtual_image() : m_nt{ nullptr }, m_base{ 0 } {};
virtual_image(const std::string_view mod) : m_base{0}, m_nt{nullptr} {
auto peb = util::peb();
if (!peb) return;
if (!peb->Ldr->InMemoryOrderModuleList.Flink) return;
auto* list = &peb->Ldr->InMemoryOrderModuleList;
for (auto i = list->Flink; i != list; i = i->Flink) {
auto entry = CONTAINING_RECORD(i, native::LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);
if (!entry)
continue;
auto name = util::wide_to_multibyte(entry->BaseDllName.Buffer);
std::transform(name.begin(), name.end(), name.begin(), ::tolower);
if (name == mod) {
m_base = uintptr_t(entry->DllBase);
auto dos = reinterpret_cast<IMAGE_DOS_HEADER*>(m_base);
m_nt = reinterpret_cast<native::nt_headers_t<true>*>(m_base + dos->e_lfanew);
parse_exports();
break;
}
}
}
void parse_exports() {
auto dir = m_nt->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT];
auto exp =
reinterpret_cast<IMAGE_EXPORT_DIRECTORY*>(m_base + dir.VirtualAddress);
if (exp->NumberOfFunctions == 0) return;
auto names = reinterpret_cast<uint32_t*>(m_base + exp->AddressOfNames);
auto funcs = reinterpret_cast<uint32_t*>(m_base + exp->AddressOfFunctions);
auto ords = reinterpret_cast<uint16_t*>(m_base + exp->AddressOfNameOrdinals);
if (!names || !funcs || !ords) return;
for (size_t i{}; i < exp->NumberOfFunctions; i++) {
uintptr_t va = m_base + funcs[ords[i]];
std::string name = reinterpret_cast<const char*>(m_base + names[i]);
m_exports[name] = va;
}
}
auto& exports() { return m_exports; }
operator bool() { return m_base != 0; }
};
struct import_t {
std::string name;
uint32_t rva;
};
struct section_t {
std::string name;
size_t size;
size_t v_size;
uint32_t rva;
uint32_t va;
};
template <bool x64 = false>
class image {
std::vector<char> m_buffer;
std::unordered_map<std::string, std::vector<import_t>> m_imports;
std::vector<section_t> m_sections;
native::nt_headers_t<x64>* m_nt;
IMAGE_DOS_HEADER* m_dos;
std::vector<std::pair<uint32_t, native::reloc_entry_t>> m_relocs;
public:
image() = default;
image(const std::vector<char>& buf) {
m_buffer.assign(buf.begin(), buf.end());
m_dos = reinterpret_cast<IMAGE_DOS_HEADER*>(m_buffer.data());
m_nt = reinterpret_cast<native::nt_headers_t<x64>*>(m_buffer.data() + m_dos->e_lfanew);
load();
}
void load() {
parse_sections();
parse_relocs();
parse_imports();
}
void parse_sections() {
auto secs = IMAGE_FIRST_SECTION(m_nt);
const size_t n = m_nt->FileHeader.NumberOfSections;
for (size_t i = 0; i < n; i++) {
auto sec = secs[i];
auto name = reinterpret_cast<const char*>(sec.Name);
m_sections.emplace_back(section_t{ name, sec.SizeOfRawData, sec.Misc.VirtualSize, sec.PointerToRawData, sec.VirtualAddress });
}
};
template<typename T = void*>
T rva_to_ptr(const uint32_t rva) {
uint8_t* output = rva + reinterpret_cast<uint8_t*>(m_dos);
for (auto& sec : m_sections) {
if (sec.va <= rva && rva < (sec.va + sec.v_size)) {
output = output - sec.va + sec.rva;
break;
}
}
return reinterpret_cast<T>(output);
}
void parse_relocs() {
const auto reloc_dir = m_nt->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC];
if (!reloc_dir.Size) return;
const auto ptr = rva_to_ptr(reloc_dir.VirtualAddress);
auto block = reinterpret_cast<native::reloc_block_t*>(ptr);
while (block->base_rva) {
for (size_t i = 0; i < block->num_entries(); ++i) {
auto entry = block->entries[i];
m_relocs.emplace_back(std::make_pair(block->base_rva, entry));
}
block = block->get_next();
}
}
void parse_imports() {
const auto import_dir = m_nt->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT];
if (!import_dir.Size) return;
const auto ptr = rva_to_ptr(import_dir.VirtualAddress);
auto table = reinterpret_cast<IMAGE_IMPORT_DESCRIPTOR*>(ptr);
for (uint32_t i = 0; i < table->Name; i = table->Name, ++table) {
auto mod_name = std::string(reinterpret_cast<char*>(rva_to_ptr(table->Name)));
auto thunk = reinterpret_cast<native::image_thunk_data_t<x64>*>(rva_to_ptr(table->OriginalFirstThunk));
auto step = x64 ? sizeof(uint64_t) : sizeof(uint32_t);
for (uint32_t index = 0; thunk->address; index += step, ++thunk) {
auto named_import = reinterpret_cast<native::image_named_import_t*>(rva_to_ptr(thunk->address));
if (!thunk->is_ordinal) {
import_t data;
data.name = reinterpret_cast<const char*>(named_import->name);
data.rva = table->OriginalFirstThunk + index;
std::transform(mod_name.begin(), mod_name.end(), mod_name.begin(), ::tolower);
m_imports[mod_name].emplace_back(std::move(data));
}
}
}
}
void copy(std::vector<char>& out) {
out.resize(m_nt->OptionalHeader.SizeOfImage);
std::memcpy(&out[0], &m_buffer[0], 4096);
for (auto& sec : m_sections) {
std::memcpy(&out[sec.va], &m_buffer[sec.rva], sec.size);
}
}
void relocate(std::vector<char>& image, uintptr_t base) {
const auto delta = base - m_nt->OptionalHeader.ImageBase;
if (delta > 0) {
for (auto& [base_rva, entry] : m_relocs) {
if (x64) {
if (entry.type == IMAGE_REL_BASED_HIGHLOW || entry.type == IMAGE_REL_BASED_DIR64) {
*reinterpret_cast<uint64_t*>(&image[base_rva + entry.offset]) += delta;
}
continue;
}
if (entry.type == IMAGE_REL_BASED_HIGHLOW) {
*reinterpret_cast<uint32_t*>(&image[base_rva + entry.offset]) += delta;
}
}
}
}
operator bool() const { return m_nt != nullptr; }
auto& imports() const { return m_imports; }
auto& relocs() const { return m_relocs; }
auto& sections() const { return m_sections; }
};
}; // namespace pe
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